The reduction of carbon emissions in the steel industry is a significant challenge,and utilizing CO_(2) from carbon intensive steel industry off-gases for methanol production is a promising strategy for decarbonizatio...The reduction of carbon emissions in the steel industry is a significant challenge,and utilizing CO_(2) from carbon intensive steel industry off-gases for methanol production is a promising strategy for decarbonization.However,steelwork off-gases typically contain various impurities,including H_(2)S,which can deactivate commercial methanol synthesis catalysts,Cu/ZnO/Al_(2)O_(3)(CZA).Reverse water-gas shift(RWGS)reaction is the predominant side reaction in CO_(2) hydrogenation to methanol which can occur at ambient pressure,enabling the decouple of RWGS from methanol production at high pressure.Then,a series of activated CZA catalysts has been in-situ pretreated in 400 ppm H_(2)S/Ar at 250℃and tested for both RWGS reaction at ambient pressure and CO_(2) hydrogenation to methanol at high pressure.An innovative decoupling strategy was employed to isolate the RWGS reaction from the methanol synthesis process,enabling the investigation of the evolution of active site structures and the poisoning mechanism through elemental analysis,X-ray Diffraction,X-ray Photoelectron Spectroscopy,Fourier Transform Infrared Spectroscopy,Temperature Programmed Reduction and CO_(2) Temperature Programmed Desorption.The results indicate that there are different dynamic migration behaviors of ZnO_(x) in the two reaction systems,leading to different poisoning mechanisms.These interesting findings are beneficial to develop sulfur resistant and durable highly efficient catalysts for CO_(2) hydrogenation to methanol,promoting the carbon emission reduction in steel industry.展开更多
BACKGROUND The primary complication associated with gestational diabetes mellitus(GDM)is delivery of an infant that is large for gestational age(LGA).Epidemiological findings have demonstrated that irregular lipid met...BACKGROUND The primary complication associated with gestational diabetes mellitus(GDM)is delivery of an infant that is large for gestational age(LGA).Epidemiological findings have demonstrated that irregular lipid metabolism significantly con-tributes to insulin resistance,a key pathophysiological mechanism in GDM.However,the correlation between various lipid indices and the probability of delivering LGA infants remains inconsistent.AIM To explore the relationships between lipid indices and the possibility of having LGA infants among GDM-affected pregnant females.METHODS Binary logistic regression methods were employed to evaluate the odds ratios and corresponding 95%confidence intervals for LGA according to five lipid indices.Restricted cubic spline models were applied to investigate dose-response relationships.The association between lipid indices and the risk of delivering LGA infants was further investigated among different subgroups.Receiver operating characteristic curves were utilized to assess the diagnostic performance of lipid indices.RESULTS Across crude and adjusted models,females with lipid indices in the upper two tertiles presented a markedly elevated risk of delivering LGA infants compared with the lowest tertile category.Conversely,high-density lipoprotein cholesterol levels demonstrated the contrary trend.Restricted cubic spline analyses revealed linear associations between the five lipid indices,except triglyceride levels,and the prevalence of LGA.The subgroup analysis highlighted that the correlation between lipid indices and the probability of LGA was inconsistent.The five lipid indices presented significant diagnostic efficacy,as indicated by receiver operating characteristic curve areas.CONCLUSION Our research demonstrated that lipid indices were effective predictors of the incidence of LGA infants in GDM-affected pregnancies irrespective of potential confounding factors.展开更多
Lamina structures,as typical sedimentary features in shale formations,determine both the quality of shale reservoirs and fracturing effects.In this study,through electric imaging logging,based on core scanning photos,...Lamina structures,as typical sedimentary features in shale formations,determine both the quality of shale reservoirs and fracturing effects.In this study,through electric imaging logging,based on core scanning photos,thin sections,and other data from the Wufeng-Longmaxi Formation shale reservoirs in the western Sichuan Block,the characteristics and classification scheme of deep shale gas reservoir laminaset were clarified.In addition,with core scale electrical images,the electrical imaging logging response characteristics of different types of laminaset were identified.Based on electrical imaging logging images,a laminaset clustering algorithm was designed to segment the laminaset and then Levenberg-Marquardt(L-M)algorithm was improved by introducing a random forest to obtain the R-L-M algorithm,which was used to extract key parameters of lam-inaset such as attitude,type,density,and thickness.The average accuracy,recall rate,and F1 score of laminaset recognition results of this algorithm were 14.82%higher than those of a well-known international commercial software(T).This method was used to evaluate the Longmaxi Formation shale gas reservoir in the western Sichuan Block.The development density of clay-siliceous(organic-lean)laminaset from the Longyi 1-4 small layer to the lower Wufeng Formation firstly decreased and then increased and the minimum value was found in Longyi 1-1 small layer.In contrast,the development density of siliceous-clay laminaset(organic-rich)first increased and then gradually decreased and the maximum value was found in Longyi 1-1 small layer.The clay-siliceous laminaset(organic matters-contained)and the calcareous-clay laminaset(organic matters-contained)showed a stable developmental trend.展开更多
The corrosion behavior and microstructure characteristics of metal inert gas(MIG)welded dissimilar joints of the 6005A alloy modified with Sc(designated as 6005A+Sc)and the 5083 alloy were investigated using corrosion...The corrosion behavior and microstructure characteristics of metal inert gas(MIG)welded dissimilar joints of the 6005A alloy modified with Sc(designated as 6005A+Sc)and the 5083 alloy were investigated using corrosion tests and microscopy techniques.Results show that the dissimilar joints exhibit strong stress corrosion cracking(SCC)resistance,maintaining substantial strength during slow strain rate tensile tests.Notably,the heat-affected zone(HAZ)and base metal(BM)on the 6005A+Sc side show superior performance in terms of inter-granular corrosion(IGC)and exfoliation corrosion(EXCO)compared to the corresponding zones on the 5083 side.The lower corrosion resistance of the 5083-BM and the 5083-HAZ can be attributed to the presence of numerous Al_(2)Mg_(3)phases and micro-scaled Al_(6)(Mn,Fe)intermetallics,mainly distributed along the rolling direction.Conversely,the enhanced corrosion resistance of the 6005A+Sc-BM and the 6005A+Sc-HAZ can be attributed to the discontinuously distributed grain boundary precipitates(β-Mg_(2)Si),the smaller grain size,and the reduced corrosive current density.展开更多
The aim of this study was to explore the impact of chronic apical periodontitis(CAP)on atherosclerosis in apoE^(−/−)mice fed high-fat diet(HFD).This investigation focused on the gut microbiota,metabolites,and intestin...The aim of this study was to explore the impact of chronic apical periodontitis(CAP)on atherosclerosis in apoE^(−/−)mice fed high-fat diet(HFD).This investigation focused on the gut microbiota,metabolites,and intestinal barrier function to uncover potential links between oral health and cardiovascular disease(CVD).In this study,CAP was shown to exacerbate atherosclerosis in HFD-fed apoE^(−/−)mice,as evidenced by the increase in plaque size and volume in the aortic walls observed via Oil Red O staining.16S rRNA sequencing revealed significant alterations in the gut microbiota,with harmful bacterial species thriving while beneficial species declining.Metabolomic profiling indicated disruptions in lipid metabolism and primary bile acid synthesis,leading to elevated levels of taurochenodeoxycholic acid(TCDCA),taurocholic acid(TCA),and tauroursodeoxycholic acid(TDCA).These metabolic shifts may contribute to atherosclerosis development.Furthermore,impaired intestinal barrier function,characterized by reduced mucin expression and disrupted tight junction proteins,was observed.The increased intestinal permeability observed was positively correlated with the severity of atherosclerotic lesions,highlighting the importance of the intestinal barrier in cardiovascular health.In conclusion,this research underscores the intricate interplay among oral health,gut microbiota composition,metabolite profiles,and CVD incidence.These findings emphasize the importance of maintaining good oral hygiene as a potential preventive measure against cardiovascular issues,as well as the need for further investigations into the intricate mechanisms linking oral health,gut microbiota,and metabolic pathways in CVD development.展开更多
BACKGROUND The birth of large-for-gestational-age(LGA)infants is associated with many shortterm adverse pregnancy outcomes.It has been observed that the proportion of LGA infants born to pregnant women with gestationa...BACKGROUND The birth of large-for-gestational-age(LGA)infants is associated with many shortterm adverse pregnancy outcomes.It has been observed that the proportion of LGA infants born to pregnant women with gestational diabetes mellitus(GDM)is significantly higher than that born to healthy pregnant women.However,traditional methods for the diagnosis of LGA have limitations.Therefore,this study aims to establish a predictive model that can effectively identify women with GDM who are at risk of delivering LGA infants.AIM To develop and validate a nomogram prediction model of delivering LGA infants among pregnant women with GDM,and provide strategies for the effective prevention and timely intervention of LGA.METHODS The multivariable prediction model was developed by carrying out the following steps.First,the variables that were associated with LGA risk in pregnant women with GDM were screened by univariate analyses,for which the P value was<0.10.Subsequently,Least Absolute Shrinkage and Selection Operator regression was fit using ten cross-validations,and the optimal combination factors were se-lected by choosing lambda 1se as the criterion.The final predictors were deter-mined by multiple backward stepwise logistic regression analysis,in which only the independent variables were associated with LGA risk,with a P value<0.05.Finally,a risk prediction model was established and subsequently evaluated by using area under the receiver operating characteristic curve,calibration curve and decision curve analyses.RESULTS After using a multistep screening method,we establish a predictive model.Several risk factors for delivering an LGA infant were identified(P<0.01),including weight gain during pregnancy,parity,triglyceride-glucose index,free tetraiodothyronine level,abdominal circumference,alanine transaminase-aspartate aminotransferase ratio and weight at 24 gestational weeks.The nomogram’s prediction ability was supported by the area under the curve(0.703,0.709,and 0.699 for the training cohort,validation cohort,and test cohort,respectively).The calibration curves of the three cohorts displayed good agreement.The decision curve showed that the use of the 10%-60%threshold for identifying pregnant women with GDM who are at risk of delivering an LGA infant would result in a positive net benefit.CONCLUSION Our nomogram incorporated easily accessible risk factors,facilitating individualized prediction of pregnant women with GDM who are likely to deliver an LGA infant.展开更多
To provide diversified services in the intelligent transportation systems,smart vehicles will generate unprecedented amounts of data every day.Due to data security and user privacy issues,Federated Learning(FL)is cons...To provide diversified services in the intelligent transportation systems,smart vehicles will generate unprecedented amounts of data every day.Due to data security and user privacy issues,Federated Learning(FL)is considered a potential solution to ensure privacy-preserving in data sharing.However,there are still many challenges to applying the traditional synchronous FL directly in the Internet of Vehicles(Io V),such as unreliable communications and malicious attacks.In this paper,we propose a Directed Acyclic Graph(DAG)based Swarm Learning(DSL),which integrates edge computing,FL,and blockchain technologies to provide secure data sharing and model training in Io Vs.To deal with the high mobility of vehicles,the dynamic vehicle association algorithm is introduced,which could optimize the connections between vehicles and road side units to improve the training efficiency.Moreover,to enhance the anti-attack property of the DSL algorithm,a malicious attack detection method is adopted,which could recognize malicious vehicles by the site confirmation rate.Furthermore,an accuracy-based reward mechanism is developed to promote vehicles to participate in the model training with honest behaviors.Finally,simulation results demonstrate that the proposed DSL algorithm could achieve better performance in terms of model accuracy,convergence rates and security compared with existing algorithms.展开更多
In the tapping-mode atomic force microscope(TM-AFM),the probe tip continuously taps the sample surface,which may cause plastic deformation of the sample and result in energy dissipation.The energy dissipation of the p...In the tapping-mode atomic force microscope(TM-AFM),the probe tip continuously taps the sample surface,which may cause plastic deformation of the sample and result in energy dissipation.The energy dissipation of the probe is closely related to the scanned phase image.To quantify the energy dissipation due to plastic indentations of the sample,this study utilized a combination of molecular dynamics(MD)simulations and experiments on single-crystal copper samples,including multiple nano-indentation tests.The energy dissipation of the probe due to the plastic deformation of the sample was calculated by integrating the hysteresis curve of the indentation depth versus the force applied to the indenter.The simulation results are in good agreement with the experimental ones.Both sets of results have demonstrated that the plastic energy dissipation decreases as the number of indentations increases,and eventually the energy of the probe tends to stabilize.This equilibrium energy dissipation is associated with other dissipation mechanisms.Furthermore,it was observed that,after hundreds of taps,the dissipated energy of plastic deformation could be ignored,implying that the scanned image may not reflect the plasticity information of the sample after multiple taps of the probe on the sample surface for scanning.展开更多
The AFM probe in tapping mode is a continuous process of energy dissipation,from moving away from to intermittent contact with the sample surfaces.At present,studies regarding the energy dissipation mechanism of this ...The AFM probe in tapping mode is a continuous process of energy dissipation,from moving away from to intermittent contact with the sample surfaces.At present,studies regarding the energy dissipation mechanism of this continuous process have only been reported sporadically,and there are no systematic explanations or experimental verifications of the energy dissipation mechanism in each stage of the continuous process.The quality factors can be used to characterize the energy dissipation in TM-AFM systems.In this study,the vibration model of the microcantilever beam was established,coupling the vibration and damping effects of the microcantilever beam.The quality factor of the vibrating microcantilever beam under damping was derived,and the air viscous damping when the probe is away from the sample and the air squeeze film damping when the probe is close to the sample were calculated.In addition,the mechanism of the damping effects of different shapes of probes at different tip–sample distances was analyzed.The accuracy of the theoretical simplified model was verified using both experimental and simulation methods.A clearer understanding of the kinetic characteristics and damping mechanism of the TM-AFM was achieved by examining the air damping dissipation mechanism of AFM probes in the tapping mode,which was very important for improving both the quality factor and the imaging quality of the TM-AFM system.This study’s research findings also provided theoretical references and experimental methods for the future study of the energy dissipation mechanism of micro-nano-electromechanical systems.展开更多
The formation of ice on the leading edge of aircraft engines is a serious issue,as it can have catastrophic consequences.The Swirl Anti-Icing(SAI)system,driven by ejection,circulates hot fluid within a 360°annula...The formation of ice on the leading edge of aircraft engines is a serious issue,as it can have catastrophic consequences.The Swirl Anti-Icing(SAI)system,driven by ejection,circulates hot fluid within a 360°annular chamber to heat the engine inlet lip surface and prevent icing.This study employs a validated Computational Fluid Dynamics(CFD)approach to study the impact of key geometric parameters of this system on flow and heat transfer characteristics within the anti-icing chamber.Additionally,the entropy generation rate and exergy efficiency are analyzed to assess the energy utilization in the system.The research findings indicate that,within the considered flow range,reducing the nozzle specific areaφfrom 0.03061 to 0.01083 can enhance the ejection coefficient by over 60.7%.This enhancement increases the air circulating rate,thereby intensifying convective heat transfer within the SAI chamber.However,the reduction inφalso leads to a significant increase in the required bleed air pressure and a higher entropy generation rate,indicating lower exergy efficiency.The nozzle angleθnotably affects the distribution of hot and cold spots on the lip surface of the SAI chamber.Increasingθfrom 0°to 20°reduces the maximum temperature difference on the anti-icing chamber surface by 60 K.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22276060 and 21976059)Guangdong Basic and Applied Basic Research Foundation(No.2024A1515012636)China Scholarship Council Scholarship(No.201906155006)。
文摘The reduction of carbon emissions in the steel industry is a significant challenge,and utilizing CO_(2) from carbon intensive steel industry off-gases for methanol production is a promising strategy for decarbonization.However,steelwork off-gases typically contain various impurities,including H_(2)S,which can deactivate commercial methanol synthesis catalysts,Cu/ZnO/Al_(2)O_(3)(CZA).Reverse water-gas shift(RWGS)reaction is the predominant side reaction in CO_(2) hydrogenation to methanol which can occur at ambient pressure,enabling the decouple of RWGS from methanol production at high pressure.Then,a series of activated CZA catalysts has been in-situ pretreated in 400 ppm H_(2)S/Ar at 250℃and tested for both RWGS reaction at ambient pressure and CO_(2) hydrogenation to methanol at high pressure.An innovative decoupling strategy was employed to isolate the RWGS reaction from the methanol synthesis process,enabling the investigation of the evolution of active site structures and the poisoning mechanism through elemental analysis,X-ray Diffraction,X-ray Photoelectron Spectroscopy,Fourier Transform Infrared Spectroscopy,Temperature Programmed Reduction and CO_(2) Temperature Programmed Desorption.The results indicate that there are different dynamic migration behaviors of ZnO_(x) in the two reaction systems,leading to different poisoning mechanisms.These interesting findings are beneficial to develop sulfur resistant and durable highly efficient catalysts for CO_(2) hydrogenation to methanol,promoting the carbon emission reduction in steel industry.
基金Supported by Nanjing Medical Science and Technique Development Foundation,No.YKK23151the Opening Foundation of Key Laboratory,No.JSHD202313+3 种基金Yingke Xinchuang Research Foundation of Jiangsu Blood Transfusion Association,No.JSYK2024006the Jiangsu Province Capability Improvement Project through Science,Technology and Education,No.ZDXYS202210Open Project of the State Key Laboratory of Reproductive Medicine of Nanjing Medical University,No.SKLRM-K202107the Jiangsu Provincial Maternal and Child Health Research Program,No.F202040.
文摘BACKGROUND The primary complication associated with gestational diabetes mellitus(GDM)is delivery of an infant that is large for gestational age(LGA).Epidemiological findings have demonstrated that irregular lipid metabolism significantly con-tributes to insulin resistance,a key pathophysiological mechanism in GDM.However,the correlation between various lipid indices and the probability of delivering LGA infants remains inconsistent.AIM To explore the relationships between lipid indices and the possibility of having LGA infants among GDM-affected pregnant females.METHODS Binary logistic regression methods were employed to evaluate the odds ratios and corresponding 95%confidence intervals for LGA according to five lipid indices.Restricted cubic spline models were applied to investigate dose-response relationships.The association between lipid indices and the risk of delivering LGA infants was further investigated among different subgroups.Receiver operating characteristic curves were utilized to assess the diagnostic performance of lipid indices.RESULTS Across crude and adjusted models,females with lipid indices in the upper two tertiles presented a markedly elevated risk of delivering LGA infants compared with the lowest tertile category.Conversely,high-density lipoprotein cholesterol levels demonstrated the contrary trend.Restricted cubic spline analyses revealed linear associations between the five lipid indices,except triglyceride levels,and the prevalence of LGA.The subgroup analysis highlighted that the correlation between lipid indices and the probability of LGA was inconsistent.The five lipid indices presented significant diagnostic efficacy,as indicated by receiver operating characteristic curve areas.CONCLUSION Our research demonstrated that lipid indices were effective predictors of the incidence of LGA infants in GDM-affected pregnancies irrespective of potential confounding factors.
基金supported by the technology project“Identification of Layered Patterns in Deep Shale Gas Reservoirs in Yuxi Block and Its Impact on Fracturing Effectiveness”(No.20230304-05)of Chongqing Shale Gas Exploration and Development Co.,Ltd.
文摘Lamina structures,as typical sedimentary features in shale formations,determine both the quality of shale reservoirs and fracturing effects.In this study,through electric imaging logging,based on core scanning photos,thin sections,and other data from the Wufeng-Longmaxi Formation shale reservoirs in the western Sichuan Block,the characteristics and classification scheme of deep shale gas reservoir laminaset were clarified.In addition,with core scale electrical images,the electrical imaging logging response characteristics of different types of laminaset were identified.Based on electrical imaging logging images,a laminaset clustering algorithm was designed to segment the laminaset and then Levenberg-Marquardt(L-M)algorithm was improved by introducing a random forest to obtain the R-L-M algorithm,which was used to extract key parameters of lam-inaset such as attitude,type,density,and thickness.The average accuracy,recall rate,and F1 score of laminaset recognition results of this algorithm were 14.82%higher than those of a well-known international commercial software(T).This method was used to evaluate the Longmaxi Formation shale gas reservoir in the western Sichuan Block.The development density of clay-siliceous(organic-lean)laminaset from the Longyi 1-4 small layer to the lower Wufeng Formation firstly decreased and then increased and the minimum value was found in Longyi 1-1 small layer.In contrast,the development density of siliceous-clay laminaset(organic-rich)first increased and then gradually decreased and the maximum value was found in Longyi 1-1 small layer.The clay-siliceous laminaset(organic matters-contained)and the calcareous-clay laminaset(organic matters-contained)showed a stable developmental trend.
基金financially supported by the Science and Technology Innovation Program of Hunan Province,China(No.2023RC3055)the Natural Science Foundation of Hunan Province,China(Nos.2023JJ30671,2020JJ4114)+5 种基金the Natural Science Foundation of Changsha City,China(No.Kq2208264)National Key Project of Research and Development Plan of China(Nos.2021YFC1910505,2021YFC1910504)the Young Core Teacher Foundation of Hunan Province,China(No.150220001)Key Research and Development Program of Guangdong Province,China(No.2020B010186002)the National Natural Science Foundation of China(No.51601229)the Key-Area Research and Development Program of Foshan City,China(No.2230032004640).
文摘The corrosion behavior and microstructure characteristics of metal inert gas(MIG)welded dissimilar joints of the 6005A alloy modified with Sc(designated as 6005A+Sc)and the 5083 alloy were investigated using corrosion tests and microscopy techniques.Results show that the dissimilar joints exhibit strong stress corrosion cracking(SCC)resistance,maintaining substantial strength during slow strain rate tensile tests.Notably,the heat-affected zone(HAZ)and base metal(BM)on the 6005A+Sc side show superior performance in terms of inter-granular corrosion(IGC)and exfoliation corrosion(EXCO)compared to the corresponding zones on the 5083 side.The lower corrosion resistance of the 5083-BM and the 5083-HAZ can be attributed to the presence of numerous Al_(2)Mg_(3)phases and micro-scaled Al_(6)(Mn,Fe)intermetallics,mainly distributed along the rolling direction.Conversely,the enhanced corrosion resistance of the 6005A+Sc-BM and the 6005A+Sc-HAZ can be attributed to the discontinuously distributed grain boundary precipitates(β-Mg_(2)Si),the smaller grain size,and the reduced corrosive current density.
基金supported by the National Natural Science Foundation of China(No.81970926)supported by the Fujian Province Natural Science Foundation of China(No.2023J01709)the Fujian Provincial Health Technology Project(No.2022QNA073).
文摘The aim of this study was to explore the impact of chronic apical periodontitis(CAP)on atherosclerosis in apoE^(−/−)mice fed high-fat diet(HFD).This investigation focused on the gut microbiota,metabolites,and intestinal barrier function to uncover potential links between oral health and cardiovascular disease(CVD).In this study,CAP was shown to exacerbate atherosclerosis in HFD-fed apoE^(−/−)mice,as evidenced by the increase in plaque size and volume in the aortic walls observed via Oil Red O staining.16S rRNA sequencing revealed significant alterations in the gut microbiota,with harmful bacterial species thriving while beneficial species declining.Metabolomic profiling indicated disruptions in lipid metabolism and primary bile acid synthesis,leading to elevated levels of taurochenodeoxycholic acid(TCDCA),taurocholic acid(TCA),and tauroursodeoxycholic acid(TDCA).These metabolic shifts may contribute to atherosclerosis development.Furthermore,impaired intestinal barrier function,characterized by reduced mucin expression and disrupted tight junction proteins,was observed.The increased intestinal permeability observed was positively correlated with the severity of atherosclerotic lesions,highlighting the importance of the intestinal barrier in cardiovascular health.In conclusion,this research underscores the intricate interplay among oral health,gut microbiota composition,metabolite profiles,and CVD incidence.These findings emphasize the importance of maintaining good oral hygiene as a potential preventive measure against cardiovascular issues,as well as the need for further investigations into the intricate mechanisms linking oral health,gut microbiota,and metabolic pathways in CVD development.
基金Supported by National Natural Science Foundation of China,No.81870546Nanjing Medical Science and Technique Development Foundation,No.YKK23151Science and Technology Development Foundation Item of Nanjing Medical University,No.NMUB20210117.
文摘BACKGROUND The birth of large-for-gestational-age(LGA)infants is associated with many shortterm adverse pregnancy outcomes.It has been observed that the proportion of LGA infants born to pregnant women with gestational diabetes mellitus(GDM)is significantly higher than that born to healthy pregnant women.However,traditional methods for the diagnosis of LGA have limitations.Therefore,this study aims to establish a predictive model that can effectively identify women with GDM who are at risk of delivering LGA infants.AIM To develop and validate a nomogram prediction model of delivering LGA infants among pregnant women with GDM,and provide strategies for the effective prevention and timely intervention of LGA.METHODS The multivariable prediction model was developed by carrying out the following steps.First,the variables that were associated with LGA risk in pregnant women with GDM were screened by univariate analyses,for which the P value was<0.10.Subsequently,Least Absolute Shrinkage and Selection Operator regression was fit using ten cross-validations,and the optimal combination factors were se-lected by choosing lambda 1se as the criterion.The final predictors were deter-mined by multiple backward stepwise logistic regression analysis,in which only the independent variables were associated with LGA risk,with a P value<0.05.Finally,a risk prediction model was established and subsequently evaluated by using area under the receiver operating characteristic curve,calibration curve and decision curve analyses.RESULTS After using a multistep screening method,we establish a predictive model.Several risk factors for delivering an LGA infant were identified(P<0.01),including weight gain during pregnancy,parity,triglyceride-glucose index,free tetraiodothyronine level,abdominal circumference,alanine transaminase-aspartate aminotransferase ratio and weight at 24 gestational weeks.The nomogram’s prediction ability was supported by the area under the curve(0.703,0.709,and 0.699 for the training cohort,validation cohort,and test cohort,respectively).The calibration curves of the three cohorts displayed good agreement.The decision curve showed that the use of the 10%-60%threshold for identifying pregnant women with GDM who are at risk of delivering an LGA infant would result in a positive net benefit.CONCLUSION Our nomogram incorporated easily accessible risk factors,facilitating individualized prediction of pregnant women with GDM who are likely to deliver an LGA infant.
基金supported in part by the National Natural Science Foundation of China(NSFC)under Grant 62371082,61831002,and 62001076in part by the Natural Science Foundation of Chongqing under Grant CSTB2023NSCQ-MSX0726 and cstc2020jcyj-msxmX0878。
文摘To provide diversified services in the intelligent transportation systems,smart vehicles will generate unprecedented amounts of data every day.Due to data security and user privacy issues,Federated Learning(FL)is considered a potential solution to ensure privacy-preserving in data sharing.However,there are still many challenges to applying the traditional synchronous FL directly in the Internet of Vehicles(Io V),such as unreliable communications and malicious attacks.In this paper,we propose a Directed Acyclic Graph(DAG)based Swarm Learning(DSL),which integrates edge computing,FL,and blockchain technologies to provide secure data sharing and model training in Io Vs.To deal with the high mobility of vehicles,the dynamic vehicle association algorithm is introduced,which could optimize the connections between vehicles and road side units to improve the training efficiency.Moreover,to enhance the anti-attack property of the DSL algorithm,a malicious attack detection method is adopted,which could recognize malicious vehicles by the site confirmation rate.Furthermore,an accuracy-based reward mechanism is developed to promote vehicles to participate in the model training with honest behaviors.Finally,simulation results demonstrate that the proposed DSL algorithm could achieve better performance in terms of model accuracy,convergence rates and security compared with existing algorithms.
基金support from the National Natural Science Foundation of China(NSFC 11572031).
文摘In the tapping-mode atomic force microscope(TM-AFM),the probe tip continuously taps the sample surface,which may cause plastic deformation of the sample and result in energy dissipation.The energy dissipation of the probe is closely related to the scanned phase image.To quantify the energy dissipation due to plastic indentations of the sample,this study utilized a combination of molecular dynamics(MD)simulations and experiments on single-crystal copper samples,including multiple nano-indentation tests.The energy dissipation of the probe due to the plastic deformation of the sample was calculated by integrating the hysteresis curve of the indentation depth versus the force applied to the indenter.The simulation results are in good agreement with the experimental ones.Both sets of results have demonstrated that the plastic energy dissipation decreases as the number of indentations increases,and eventually the energy of the probe tends to stabilize.This equilibrium energy dissipation is associated with other dissipation mechanisms.Furthermore,it was observed that,after hundreds of taps,the dissipated energy of plastic deformation could be ignored,implying that the scanned image may not reflect the plasticity information of the sample after multiple taps of the probe on the sample surface for scanning.
基金the National Natural Science Foun-dation of China(Grant No.11572031).
文摘The AFM probe in tapping mode is a continuous process of energy dissipation,from moving away from to intermittent contact with the sample surfaces.At present,studies regarding the energy dissipation mechanism of this continuous process have only been reported sporadically,and there are no systematic explanations or experimental verifications of the energy dissipation mechanism in each stage of the continuous process.The quality factors can be used to characterize the energy dissipation in TM-AFM systems.In this study,the vibration model of the microcantilever beam was established,coupling the vibration and damping effects of the microcantilever beam.The quality factor of the vibrating microcantilever beam under damping was derived,and the air viscous damping when the probe is away from the sample and the air squeeze film damping when the probe is close to the sample were calculated.In addition,the mechanism of the damping effects of different shapes of probes at different tip–sample distances was analyzed.The accuracy of the theoretical simplified model was verified using both experimental and simulation methods.A clearer understanding of the kinetic characteristics and damping mechanism of the TM-AFM was achieved by examining the air damping dissipation mechanism of AFM probes in the tapping mode,which was very important for improving both the quality factor and the imaging quality of the TM-AFM system.This study’s research findings also provided theoretical references and experimental methods for the future study of the energy dissipation mechanism of micro-nano-electromechanical systems.
基金Shenyang Key Laboratory of Aircraft Icing and Ice Protection,Grant Number XFX20220303Education Department of Hunan Province,China,Grant Number 23A0504National Natural Science Foundation of China,Grant Number 52275108.
文摘The formation of ice on the leading edge of aircraft engines is a serious issue,as it can have catastrophic consequences.The Swirl Anti-Icing(SAI)system,driven by ejection,circulates hot fluid within a 360°annular chamber to heat the engine inlet lip surface and prevent icing.This study employs a validated Computational Fluid Dynamics(CFD)approach to study the impact of key geometric parameters of this system on flow and heat transfer characteristics within the anti-icing chamber.Additionally,the entropy generation rate and exergy efficiency are analyzed to assess the energy utilization in the system.The research findings indicate that,within the considered flow range,reducing the nozzle specific areaφfrom 0.03061 to 0.01083 can enhance the ejection coefficient by over 60.7%.This enhancement increases the air circulating rate,thereby intensifying convective heat transfer within the SAI chamber.However,the reduction inφalso leads to a significant increase in the required bleed air pressure and a higher entropy generation rate,indicating lower exergy efficiency.The nozzle angleθnotably affects the distribution of hot and cold spots on the lip surface of the SAI chamber.Increasingθfrom 0°to 20°reduces the maximum temperature difference on the anti-icing chamber surface by 60 K.
